Intracardiac echocardiography-guided catheter ablation of highly symptomatic accelerated idioventricular rhythm originating from the right ventricular apical diverticulum.

Ventricular diverticula are saccule-like structures formed by the protrusion of the ventricular myocardium from the endocardial surface towards the free wall. Most diverticula are muscular structures, and patients usually have no obvious clinical symptoms. However, diverticula may contribute to arrhythmogenesis due to localized myocardial structural disturbances. Right ventricular apical diverticulum (RVAD) is very rare, and we report a case of highly symptomatic accelerated idioventricular rhythm (AIVR) originating from the RVAD that underwent intracardiac echocardiography (ICE)-guided catheter ablation with no recurrence during follow-up.

Accelerated idioventricular rhythm as a manifestation of chronic renocardiac syndrome: A case report.

In this case report, we describe a patient who presented with chronic symptoms and signs of uremia and persistent accelerated idioventricular rhythm (AIVR) on electrocardiogram. Findings from blood tests, echocardiography, renal ultrasound, and renal scan were suggestive of heart failure with reduced ejection fraction and chronic kidney disease, and attendance of daily hemodialysis sessions led to the restoration of sinus rhythm. Typically, AIVR has a favorable prognosis and, if necessary, medical intervention focuses on addressing the underlying responsible causes. Accumulation of uremic toxins has the potential to trigger the formation of AIVR and clearance of small solutes through conventional hemodialysis may contribute to sinus rhythm restoration.

Accelerated idioventricular rhythm after left bundle branch pacing lead implantation.

Premature ventricular contractions with right bundle branch block morphology induced during left bundle branch (LBB) pacing (LBBP) lead implantation serve as a marker indicating that the lead is close to or has reached the LBB region. However, no reports to date have described accelerated idioventricular rhythm (AIVR) induced by LBBP lead deployment. We herein describe a patient who underwent LBBP for complete atrioventricular block. The patient's intrinsic escape rhythm was overtaken by AIVR induced immediately after LBBP lead deployment. AIVR is another marker indicating that the lead has reached the LBB region.

Frequent accelerated idioventricular rhythm in an otherwise healthy child: a case report and review of literature.

BACKGROUND: Accelerated idioventricular rhythm (AIVR) is a wide QRS complex dysrhythmia that, as far as pediatric population is concerned, occurs mostly in children with underlying systemic or heart disease. Its clinical course is thought to be typically benign in otherwise healthy children and treatment to be completely needless. Existing guidelines/recommendations are based entirely on cases that had low daily burden of AIVR, and those referring to treatment itself are very unspecific. Pharmacologic therapy has been mostly unsuccessful and catheter ablation as a way of treatment has been only sporadically reported. This article is a case report with a literature review that aims to practically separate the age groups into newborn and older children and to emphasize the different clinical outcomes of children with occasional and frequent AIVR. There are only a few cases so far describing undesirable outcomes of this condition, and most of these patients had high daily burden of AIVR. To be more specific, among 38 healthy children older than 1 year reported in total, 6 had undesirable outcomes, short-term in terms of developing malignant arrhythmia or long-term in terms of developing cardiomyopathy/heart failure. CASE PRESENTATION: An 11-year-old boy had been referred to our center for a workup of incidentally discovered wide-complex arrhythmia. He was asymptomatic, with no underlying cardiac or systemic diseases. Continuous heart rate monitoring detected AIVR during most time of monitoring. In 24-h Holter-ECG, wide QRS complexes accounted for 73%. With parental consent, we conducted an electrophysiological study accompanied by radiofrequent ablation of ectopic focus, which lead to an instantaneous sinus rhythm that continued during the entire follow-up. CONCLUSION: AIVR is a rare dysrhythmia in the pediatric population, typically considered benign. Nevertheless, more than a few cases evidence its harmful potential, short-term in terms of developing malignant arrhythmia or long-term in terms of developing cardiomyopathy. Gathering more knowledge and experience along with conducting further studies is essential for the enhancement of understanding this condition, and selecting potentially vulnerable patients as well as their treatment.

Hypothermia-induced accelerated idioventricular rhythm after cardiac surgery; a case report.

BACKGROUND: Accelerated idioventricular rhythm (AIVR) is a slow ventricular arrhythmia, commonly due to myocardial ischemia in coronary artery disease. It is a transitory rhythm that rarely causes hemodynamic instability or necessitates any specific therapy. Besides, the common predisposing factors for ventricular arrhythmias after open-heart surgery are hemodynamic instability, electrolyte imbalances, hypoxia, hypovolemia, myocardial ischemia and infarction, acute graft closure, reperfusion injury, and administration of inotropes and antiarrhythmic drugs. Here we report a case of AIVR after cardiac surgery, mostly due to hypothermia that to our knowledge, it is the first report. CASE PRESENTATION: We describe a 76-year-old man presenting with typical chest pain. Following routine investigations, the patient underwent coronary artery bypass grafting. Postoperatively, he was transferred to the intensive care unit with good hemodynamic status. However, about 3 h later, he developed rhythm disturbances, leading to hemodynamic instability without response to volume replacement or inotropic support. His rhythm was AIVR, although, at first glance, it resembled the left bundle branch block. Given his unstable hemodynamic status, he was emergently transferred to the operating room. Cardiopulmonary bypass (CPB) was resumed for hemodynamic support. After the patient was rewarmed to about 35 ºC, AIVR returned to normal. He was weaned from CPB successfully and with an uneventful hospital course. CONCLUSIONS: Hypothermia is a potential cause of rhythm disturbance. Preventing the causes of arrhythmias, including hypothermia, is the best strategy.

Wide complex rhythm in a well neonate: Where are the P waves?

A neonate was seen for an evolving broad QRS complex rhythm initially captured at birth as intermittent escape beats on electrocardiogram. Continuous monitoring recorded features mimicking pre-excitation, but closer analysis revealed a regular broad QRS complex rhythm with isorhythmic atrioventricular dissociation, favouring a ventricular source. Treatment with flecainide and propranolol achieved successful control of the incessant arrhythmia with improvement in cardiac function on echocardiogram.

Accelerated idioventricular rhythm in a healthy newborn: frightening but non-threatening.

Accelerated idioventricular rhythm is a rare but benign form of ventricular tachycardia which might be challenging to differentiate from other more worrisome forms. We present the case of a healthy newborn diagnosed with an accelerated idioventricular rhythm which is spontaneously terminated without the need for medical therapy.

Clinical characteristics and therapeutic strategy of frequent accelerated idioventricular rhythm.

BACKGROUND: Accelerated idioventricular rhythm (AIVR) is often transient, considered benign and requires no treatment. This observational study aims to investigate the clinical manifestations, treatment, and prognosis of frequent AIVR. METHODS: Twenty-seven patients (20 male; mean age 32.2 ± 17.0 years) diagnosed with frequent AIVR were enrolled in our study. Inclusion criteria were as follows: (1) at least three recordings of AIVR on 24-h Holter monitoring with an interval of over one month between each recording; and (2) resting ectopic ventricular rate between 50 to 110 bpm on ECG. Electrophysiological study (EPS) and catheter ablation were performed in patients with distinct indications. RESULTS: All 27 patients experienced palpitation or chest discomfort, and two had syncope or presyncope on exertion. Impaired left ventricular ejection fraction (LVEF) was identified in 5 patients, and LVEF was negatively correlated with AIVR burden (P < 0.001). AIVR burden of over 73.8%/day could predict impaired LVEF with a sensitivity of 100% and specificity of 94.1%. Seventeen patients received EPS and ablation, five of whom had decreased LVEF. During a median follow-up of 60 (32, 84) months, LVEF of patients with impaired LV function returned to normal levels 6 months post-discharge, except one with dilated cardiomyopathy (DCM). Two patients died during follow-up. The DCM patient died due to late stage of heart failure, and another patient who refused ablation died of AIVR over-acceleration under fever. CONCLUSIONS: Frequent AIVR has unique clinical manifestations. AIVR patients with burden of over 70%, impaired LVEF, and/or symptoms of syncope or presyncope due to over-response to sympathetic tone should be considered for catheter ablation.

COVID-19-associated multisystem inflammatory syndrome in children presenting uniquely with sinus node dysfunction in the setting of shock.

SARS-CoV-2, which causes the disease COVID-19, generally has a mild disease course in children. However, a severe post-infectious inflammatory process known as multisystem inflammatory syndrome in children has been observed in association with COVID-19. This inflammatory process is a result of an abnormal immune response with similar clinical features to Kawasaki disease. It is well established that multisystem inflammatory syndrome in children is associated with myocardial dysfunction, coronary artery dilation or aneurysms, and occasionally arrhythmias. The most common electrocardiographic abnormalities seen include premature atrial or ventricular ectopy, variable degrees of atrioventricular block, and QTc prolongation, and rarely, haemodynamically significant arrhythmias necessitating extracorporeal membrane oxygenation support. However, presentation with fever, hypotension, and relative bradycardia with a left axis idioventricular rhythm has not been previously reported. We present a case of a young adolescent with multisystem inflammatory syndrome in children with myocarditis and a profoundly inappropriate sinus node response to shock with complete resolution following intravenous immunoglobulin.

Accelerated Idioventricular Rhythm: A Rare Case of Wide-Complex Dysrhythmia in a Teenager.

BACKGROUND: Accelerated idioventricular rhythm (AIVR) is an uncommon and typically benign dysrhythmia with similarities to more malignant forms of ventricular tachycardia (VT). It is often seen in adults after myocardial infarctions, although it also arises in the newborn period, as well as in children with and without congenital heart disease. CASE REPORT: We describe a presentation of AIVR in an otherwise healthy 13-year-old girl, discovered on arrival to the pediatric emergency department in the setting of post-tonsillectomy bleeding. The case reviews the diagnostic criteria of AIVR, associated symptoms, the pathophysiologic origin of AIVR, and potential treatment strategies. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Given its morphologic similarities to life-threatening forms of VT, AIVR can be misdiagnosed in the emergency department or primary care settings. With an understanding of the dysrhythmia's unique features, emergency physicians can avoid unnecessary interventions and provide the correct diagnosis, workup, and management of AIVR for pediatric patients.

Incessant accelerated idioventricular rhythm mimicking preexcitation.

ECG of patients with Wolf Parkinson White (WPW) syndrome may simulate other entities such as myocardial infarction, ventricular premature complexes, ventricular bigeminy, accelerated idioventricular rhythm, intermittent bundle branch block or electrical alternans. On the other hand, the opposite can also occur where these other conditions may simulate WPW. We present the case of a young patient referred for WPW ablation showing an incessant accelerated idioventricular rhythm mimicking preexcitation.

Intravenous Sotalol for the Treatment of Ventricular Dysrhythmias in an Infant on Extracorporeal Membrane Oxygenation.

Sotalol is a class III anti-arrhythmic agent with beta receptor blocking properties. Intravenous (IV) sotalol may be useful to treat refractory atrial and ventricular arrhythmias. A report on the efficacy and safety of IV sotalol in an infant on extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT), who developed refractory ventricular arrhythmias following surgery for congenital heart disease. A 10-day old infant with severe pulmonary valve stenosis underwent surgical pulmonary valvectomy and enlargement of the main pulmonary artery. Post-operatively, the patient developed hemodynamically significant accelerated idioventricular rhythm which was not responsive to a combination of amiodarone, lidocaine, and procainamide leading to 2 cardiac arrest events and placement on ECMO. The amiodarone infusion was uptitrated to 20 mcg/kg/min, but episodes of the hemodynamically compromising arrhythmia continued. Amiodarone was discontinued and IV sotalol was initiated at 42 mg/m2/day, divided to 3 doses, and administered every 8 h, which completely suppressed the arrhythmia. The initial sotalol dose was calculated based on a daily dose of 90 mg/m2 and reduced by an age-related factor as recommended by the FDA approved prescribing information. Subsequently, acute kidney injury requiring CRRT developed. The patient remained on IV sotalol for 3 weeks and then transitioned to oral sotalol. The oral dose was increased to 44 mg/m2/day (3.5 mg every 8 h) to account for the difference in bioavailability between the IV and oral formulations. Serial sotalol levels during IV and PO therapy remained therapeutic on ECMO and CRRT. The patient maintained normal sinus rhythm on sotalol without adverse events. IV sotalol in the setting of ECMO and CRRT was safe and effective in controlling refractory hemodynamically compromising accelerated idioventricular rhythm unresponsive to amiodarone.

Accelerated idioventricular rhythm resulting in torsades de pointes and cardiac arrest in a child: successfully cryoablated in left'coronary cusp.

Known as a benign arrhythmia and normally requiring no specific treatment, accelerated idioventricular rhythm can rarely degenerate to a life-threatening arrhythmia. Here, we present a child with left coronary cusp-originating accelerated idioventricular rhythm, degenerating into torsades de pointes and resulting in cardiac arrest, which was ablated with a cryocatheter. An 11-year-old boy, followed due to asymptomatic accelerated idioventricular rhythm before, was referred to our department because he had experienced an aborted cardiac arrest during sleep. He had been resuscitated for 5 minutes. Twenty-four-hour Holter-ECG revealed incessant accelerated idioventricular rhythm, consisting up to 90% of the whole record and two torsades de pointes attacks, triggered by accelerated idioventricular rhythm-induced "R on T" phenomenon, and resulting in syncope and cardiac arrest. Transthoracic echocardiography revealed no structural cardiac defect but mild left ventricular systolic dysfunction with an ejection fraction of 45% and shortening fraction 23%. An electrophysiologic study was conducted, and accelerated idioventricular rhythm focus was mapped to left aortic coronary cusp. A cryocatheter with an 8-mm tip was preferred for successful ablation of the accelerated idioventricular rhythm focus, due to close neighbourhood to coronary ostium. The patient was discharged in 3 days without any premature ventricular contractions or accelerated idioventricular rhythm and with normalised cardiac functions. After 9 months on follow-up, he was still asymptomatic, without any premature ventricular contractions or accelerated idioventricular rhythm and with normal cardiac functions. Although the clinical course of accelerated idioventricular rhythm is known as benign, accelerated idioventricular rhythm can rarely degenerate to a life-threatening arrhythmia. In such cases, electrophysiologic study and catheter ablation are a good option in such cases with accelerated idioventricular rhythm for an ultimate cure.

Prenatal diagnosis and prognosis of accelerated idioventricular rhythm.

OBJECTIVES: As postnatal identification of accelerated idioventricular rhythm (AIVR) relies on specific electrocardiographic patterns, prenatal diagnosis of this condition is challenging and its true incidence is unknown. The objectives of this study were to evaluate the performance of prenatal ultrasonography in identifying intrauterine cardiocirculatory events linked to specific electrocardiographic signs of postnatal AIVR, including left or right ventricular origin, and to assess the prenatal prognosis of this arrhythmia. METHODS: We reviewed Doppler tracings from the superior vena cava/ascending aorta (SVC/Ao), ductus venosus (DV), ductus arteriosus (DA) and aortic isthmus (AoI), as well as simultaneous M-mode recordings of septal and left ventricular wall motions of fetuses diagnosed with AIVR from January 2004 to December 2014. RESULTS: Three cases of AIVR were identified among 27 912 fetuses. SVC/Ao Doppler flow recordings revealed atrioventricular dissociation (ventricular rates within 20% of atrial rates) in all three fetuses and episodes of isorhythmic atrioventricular dissociation in one, while M-mode confirmed normal left ventricular shortening fraction in all cases. Fusion beats were observed on AoI tracing in one fetus, while simultaneous recordings of AoI and DA revealed signs of right bundle branch block in one case and left bundle branch block in the other two. On DV Doppler recordings, retrograde a-waves in the presence of simultaneous atrial and ventricular contractions were observed in all three fetuses, leading to an increase in central venous pressure in all and hydrops fetalis in two cases without evidence of ventricular dysfunction. CONCLUSIONS: Echocardiographic criteria required for postnatal diagnosis of AIVR can be documented in utero using specific ultrasonographic approaches. During fetal life, AIVR may not be a benign entity. Hydrops fetalis is frequently associated with AIVR because of increase in central venous pressure related to simultaneous atrioventricular contractions; thus, the ultrasonographic investigation protocol of fetuses with unexplained hydrops fetalis should aim at ruling out AIVR and include Doppler flow recordings in SVC/Ao, DV, AoI, DA and umbilical vein. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Ventricular tachycardia in a child with diabetic ketoacidosis without heart disease.

Ventricular tachycardia is uncommon in children without CHD. We present the case of a 15-year-old boy who presented with severe diabetic ketoacidosis and ventricular tachycardia and was not responsive to traditional anti-arrhythmic therapy. This case highlights the importance of identification of the underlying metabolic derangement causing the arrhythmia to provide appropriate management.

Accelerated idioventricular rhythm unmasking the brugada electrocardiographic pattern.

It has recently been reported that a high-degree right bundle branch block (RBBB) may conceal the electrocardiographic manifestations of the Brugada ECG pattern. An 82-year-old with recent onset palpitations was seen in clinic. The resting ECG showed sinus rhythm, high-degree RBBB, and an irregular idioventricular rhythm. Some fusion beats between sinus rhythm and idioventricular rhythm occurred spontaneously depicting incomplete RBBB pattern and a clear cut elevation of the ST-segment was unveiled, giving rise to a suspicious Brugada ECG pattern. The mechanisms and implications of these findings are discussed.

Transient post-reperfusion left bundle branch block and accelerated idioventricular rhythm with paradoxical QRS narrowing.

Accelerated idioventricular rhythm (AIVR) commonly follows coronary reperfusion and has been called a "reperfusion arrhythmia". Transient left bundle branch block (LBBB) is only rarely seen after interventional reperfusion and is usually considered a procedural complication. We report herein electrocardiograms (ECGs) in a case of acute lateral myocardial infarction which demonstrate both post-perfusion AIVR and a simultaneous transient LBBB with fusion complexes causing paradoxical QRS narrowing.

Idioventricular Rhythm: A Rare Presentation of Left Ventricular Pseudoaneurysm Following Radiofrequency Ablation.

Left ventricular pseudoaneurysm (PsA) is a rare complication of radiofrequency ablation (RFA) of cardiac arrhythmias. Presentation can vary widely in terms of timeline, signs, and symptoms. Idioventricular rhythm is a rare presentation of PsA post-ablation. No cases of post-ablation PsA presenting with idioventricular rhythm have been reported in the literature to date. A 72-year-old male presented with symptomatic idioventricular rhythm 34 days post RFA for premature ventricular complexes (PVCs). A PsA involving the distal anterolateral of his left ventricle wall was identified on transthoracic echo and computed tomography (CT). This patient underwent surgical patch repair which resolved his ventricular arrhythmia.

LEOPARD syndrome with accelerated idioventricular rhythm and systolic anterior motion of the posterior mitral leaflet: a case report.

Background: PTPN11 is ubiquitously expressed and has a variety of phenotypes even in a single heart. We examined LEOPARD syndrome (LS) in a patient with PTPN11 variants through pathological, electrophysiological, and anatomical studies. Case summary: A 49-year-old man with no previous medical history was brought to our emergency department because of syncope. An electrocardiogram (ECG) revealed alternating bundle branch block, and echocardiography revealed hypertrophic cardiomyopathy-like morphology with systolic anterior motion of the posterior mitral valve. Atrioventricular block, left ventricular outflow tract (LVOT) obstruction, and ventricular tachycardia were considered the differential diagnoses; however, the treatment plan was difficult to determine. An electrophysiological study revealed the cause of the ECG abnormality to be accelerated idioventricular rhythm, and the programmed ventricular stimulation was negative. Genetic testing revealed LS with PTPN11 variant, which was speculated to be the cause of these various unique cardiac features. The cause of syncope was considered to be exacerbation of LVOT obstruction due to dehydration, and the patient was treated with oral beta-blockers. Implantable loop recorder observation for 1 year revealed no arrhythmia causing syncope, and an implantable cardioverter-defibrillator and pacemaker were deemed unnecessary for primary prevention of syncope. During 2.5 years of follow-up, the LVOT peak velocity fluctuated between 2.5 and 3.5 m/s, but the patient remained stable with no recurrent syncope. Conclusion: We confirmed that LS is distinct from other cardiomyopathies using characterization, physiological, electrophysiological, and pathological examinations. Evidence supporting a specific treatment strategy for LS is limited, and understanding the pathogenesis may help establish effective treatment strategies.